Utilization of superconductive equipment in a wide variety of applications--e.g., as apparatus associated with the generation of energy, such as a nuclear fusion reactor, a superconductive generator, and an apparatus for the storage of electric power; high energy physical apparatus, such as an accelerator; transportation equipment such as a magnetic floating train and an appratus for propelling ships; and medical apparatus, such as an apparatus for treating diseases using .pi.-meson--has been gradually realized. With a great advance in such equipment and the production of large sized apparatus, it has been desired to develop superconductive materials which are capable of withstanding high magnetic fields and high-speed excitation.
For example, in magnetic fields as high as at least 8 tesla, there are usually employed superconductive wires which are made of compounds, such as Nb.sub.3 Sn and V.sub.3 Ga, having excellent high magnetic field characteristics. These wires, however, have the disadvantage that they are mechanically brittle. Therefore, various improved processes for the production of such superconductive wires have been proposed to overcome the above-described problem. For example, discontinuous fiber-shaped superconductive wire materials have been produced. These superconductive wire materials are produced by a process comprising solidifying a copper-base alloy containing low concentrations of niobium and tin components by rapidly cooling to finely disperse niobium particles in the matrix of copper, drawing the thus-formed alloy to form niobium fibers, and then applying heat treatment on the surface of the niobium fiber to form Nb.sub.3 Sn, or alternatively, a process comprising press sintering a mixture of niobium powder and copper and tin powders, or a coppertin alloy powder, producing fine short fibers, and then applying heat treatment on the surface of the fine short fiber to form Nb.sub.3 Sn.
In the discontinuous fiber-shaped superconductive wire materials produced by the above-described processes, eletric current is allowed to pass therethrough by the adjacent effect of discontinuous fiber-shaped superconductive substances. Therefore, even if the wire materials are deformed by the action of electromagnetic force, their superconductive current characteristics are not reduced as long as the distance between the superconductive substances is maintained at a lower level than a predetermined value.
In order to produce the above-described excellent discontinuous fiber-shaped superconductive wire materials or superconductive materials, it is necessary to use powdery or short fiber-shaped superconductive substances having excellent superconductive characteristics. An industrial method of production of such superconductive substances has not yet been established.